package cn.myweixin.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

public class CheckUtil {
	private static String token = "myweixin";
	public static boolean checkSignature(String signature, String timestamp, String nonce){
		
		String [] arr=new String[]{token, timestamp, nonce};
		Arrays.sort(arr);
		
		StringBuilder builder=new StringBuilder();
		for(int i=0;i<arr.length;i++){
			builder.append(arr[i]);
		}
		MessageDigest digest=null;
		String tmstr=null;
		
		
		try {
			digest=MessageDigest.getInstance("SHA-1");
			// 将三个参数字符串拼接成一个字符串进行sha1加密  
			byte[] bs=digest.digest(builder.toString().getBytes());
			tmstr=byteToStr(bs);
			
		} catch ( NoSuchAlgorithmException e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		builder=null;
		
		return tmstr!=null?tmstr.equals(signature.toUpperCase()):false;
		
	}
	
	private static String byteToStr(byte[] byteArray) {  
        String strDigest = "";  
        for (int i = 0; i < byteArray.length; i++) {  
            strDigest += byteToHexStr(byteArray[i]);  
        }  
        return strDigest;  
    }  
  
    /** 
     * 将字节转换为十六进制字符串 
     *  
     * @param mByte 
     * @return 
     */  
    private static String byteToHexStr(byte mByte) {  
        char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };  
        char[] tempArr = new char[2];  
        tempArr[0] = Digit[(mByte >>> 4) & 0X0F];  
        tempArr[1] = Digit[mByte & 0X0F];  
  
        String s = new String(tempArr);  
        return s;  
    }  
}
